Fan control system and method for controlling fan speed

ABSTRACT

A fan control system for processor is provided. The system has: a fan, configured to cool the processor; a power measurement module, coupled between the processor and a power supply of the processor, configured to measure the power of the processor; and a control module, coupled between the fan and the power measurement module, configured to control a speed of the fan according to the power of the processor, wherein when the power is higher than a predetermined power upper limit, the control module control the fan to increase the rotation speed.

CROSS REFERENCE TO RELATED APPLICATIONS

This Non-provisional application claims priority under 35 U.S.C. §119(a)on Patent Application No(s).102,129,097, filed in Taiwan, Republic ofChina on Aug. 14, 2013, the entire contents of which are herebyincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fan control system for processor anda method for controlling the fan rotation speed.

2. Description of the Related Art

Nowadays, computer system is usually configured with a centralprocessing unit which provides higher performance, but consumes moreenergy and produces more heat. In the prior art, fans are often disposedwith the processors to dissipate the heat for preventing the processorsfrom being damaged by the heat.

A typical fan control system is shown in the patent document U.S. Ser.No. 13/302253. FIG. 1 is a schematic diagram of the fan control systemin the patent document U.S. Ser. No. 13/302253. In this Fig., the fancontrol system 100 comprises a temperature sensing module 120, anembedded controller 130, and a fan 140, where the fan 140 is used todissipate the heat from the central processing unit (CPU). Thetemperature sensing module 120 measures the temperature of the CPU 110and provides the temperature data to the embedded controller 130, andthen the embedded controller 130 controls the rotation speed of the fan140 according to the temperature data, thus preventing the CPU 110 frombeing damaged by the heat.

Generally, the CPU improves its performance by increasing operatingfrequency. However, when the temperature rise of the CPU is detected,the operating frequency of the CPU may have been already increased for awhile. In other words, the temperature-based method cannot control therotation speed of the fan immediately, thus leading to the extension ofthe cooling time and a poor efficiency. Therefore, the present inventionprovides a new fan control technique for improving temperature controlefficiency.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a fan control system for processor. Thesystem comprises: a fan, configured to cool the processor; a powermeasurement module, coupled between the processor and a power supply ofthe processor, configured to measure the power of the processor; and acontrol module, coupled between the fan and the power measurementmodule, configured to control a speed of the fan according to the powerof the processor, wherein when the power is higher than a predeterminedpower upper limit, the control module control the fan to increase therotation speed.

The present invention further provides a fan rotation speed controllingmethod. The method comprises: measuring the power of the processor;controlling a rotation speed of a fan according to the power of theprocessor. The controlling step further comprises: controlling the fanto increase the rotation speed when the power is higher than apredetermined power upper limit; and controlling the fan to decrease therotation speed when the power is lower than a predetermined power lowerlimit.

A detailed description is given in the following embodiments withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be more fully understood by reading thesubsequent detailed description and examples with references made to theaccompanying drawings, wherein:

FIG. 1 is a schematic diagram of the fan control system in the priorart.

FIG. 2 is a schematic diagram of the fan control system according to anembodiment of the present invention.

FIG. 3 is a schematic diagram of the fan control system according to apreferred embodiment of the present invention.

FIG. 4 is a schematic diagram of the fan control system according to anembodiment of the present invention.

FIG. 5 is a flow chart of the method for controlling the fan controlsystem according to an embodiment of the present invention.

FIG. 6 is a flow chart of the method for controlling the fan controlsystem according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following description is of the best-contemplated mode of carryingout the invention. This description is made for the purpose ofillustrating the general principles of the invention and should not betaken in a limiting sense. The scope of the invention is best determinedby reference to the appended claims.

Fan Control System

To improve the disadvantages of the prior art, the present inventionprovides a new fan control system. With the fan control system of thepresent invention, the temperature control efficiency can besignificantly improved.

FIG. 2 is a schematic diagram of the fan control system according to anembodiment of the present invention. The fan control system 200 at leastcomprises a control module 232, a fan 240 and a power measurement module260. The fan 240 of the present invention can be used to cool down aprocessor 210 of a computer system, and the rotation speed of the fan240 can be controlled by the control module 232. In this embodiment, theprocessor 210 obtains the power from the power supply 250. The powermeasurement module 260 of the present invention is coupled between theprocessor 210 and the power supply 250 for measuring the power that theprocessor 210 consumes.

The control module 232 is coupled between the fan 240 and the powermeasurement module 260, and can control the rotation speed of the fan240 according to the power of the processor 210 which is measured by thepower measurement module 260. For example, in an embodiment, the controlmodule 232 can set a predetermined power range, which has a power upperlimit and a power lower limit. When the power measured by the powermeasurement module 260 is higher than the predetermined power upperlimit, it means that the temperature of the processor 210 is going torise, and the control module 232 has to control the fan 240 to increaseits rotation speed. Oppositely, when the power measured by the powermeasurement module 260 is lower than the predetermined power lowerlimit, it means that there is no danger of overheating in the processor210, and the control module 232 can control the fan 240 to decrease itsrotation speed in order to save the power. Note that the processor 210always varies its power earlier than its temperature. Therefore, bycontrolling the rotation speed of the fan according to the power, thetemperature of the processor 210 can be adjusted faster and earlier,thus shortening the control time and improving the control efficiency.

In some other embodiments, the predetermined power range set by thecontrol module 232 can be zero, and the predetermined power upper andthe lower limits are with the same value. In some embodiments, thecontrol module 232 can obtain the rotation speed from a lookup table (acorrespondence table between rotation speed and power), throughfunctions, and/or the combination thereof. The lookup table can bestored in various memories that can be either integrated into orseparated from the control module 232. Various techniques such as linearor non-linear interpolations can be used to compute the values of therotation speed. The present invention should not be limited to theprevious embodiments, and those skilled in the art can determine therelationship between the rotation speed of the fan and the power of theprocessor according to the spirit of the present invention.

In an embodiment, the control module 232 of the present invention can beintegrated into the embedded controller 230 of the computer system, andthe embedded controller 230 may have a variety of other functions.

FIG. 3 is a schematic diagram of the fan control system according to apreferred embodiment of the present invention. Similarly to theembodiment in FIG. 2, the fan control system 300 in this embodiment atleast has a control module 332, a fan 340 and a power measurement module360. The fan 340 can be used to cool down a processor 310 of a computersystem, and the rotation speed of the fan 340 can be controlled by thecontrol module 332. In this embodiment, the processor 310 obtains thepower from the power supply 350. The power measurement module 360 of thepresent invention is coupled between the processor 310 and the powersupply 350 for measuring the power that the processor 310 consumes. Thecontrol module 332 can be disposed in an embedded controller 330. Inthis preferred embodiment, the power measurement module 360 comprises acurrent sensing unit 362. The current sensing unit 362 is used tomeasure the current that the power supply 350 provides to the processor310. Therefore, in this embodiment, the control module 332 can calculatethe power of the processor 310 according to the current measured by thecurrent sensing unit 362. Those skilled in the art can understand thatthe power of an electronic component is the function of its current andvoltage. In an embodiment, the voltage of the processor 310 can beobtained through estimation. Specifically, the voltage of the processor310 can be read from a lookup table (a correspondence table between thevoltage and current) stored in the control module 332. Note that thevoltage usually has much smaller variation than the current on theprocessor, and in some embodiments, the voltage can be regarded as afixed value. Therefore, with this manner, the control module 332 canefficiently calculate the power that the processor 310 consumes.

FIG. 4 is a schematic diagram of the fan control system according to anembodiment of the present invention. Similarly to the embodiment in FIG.3, the fan control system 400 in this embodiment at least comprises acontrol module 432, a fan 440 and a power measurement module 460. Thefan 440 can be used to cool down a processor 410 of a computer system,and the rotation speed of the fan 440 is controlled by the controlmodule 432. In this embodiment, the processor 410 obtains power from apower supply 450. The power measurement module 460 of the presentinvention is coupled between the processor 410 and the power supply 450,and can measure the power that the processor 410 consumes. The controlmodule 432 can be disposed in an embedded controller 430. In thisembodiment, the power measurement module 460 comprises a current sensingunit 462 and a voltage sensing unit 464. The current sensing unit 462 isused to measure the current that the power supply 450 provides to theprocessor 410, and the voltage sensing unit 464 is used to measure thevoltage that the power supply 450 provides to the processor 410.Therefore, in this embodiment, the control module 462 can easilycalculate the power of the processor 410 according to the current sensedby the current sensing unit 462 and the voltage sensed by the currentsensing unit 464. With respect to the embodiments in FIG. 3 whichobtains the voltage from estimation, the method in this embodiment canobtain a more accurate voltage value and a more accurate power value.However, the circuitry in this embodiment is more complicated andexpensive.

In some embodiment, the fan control system of the present inventionfurther comprises a temperature sensing module (e.g., the temperaturesensing modules 220, 320 and 420 in FIGS. 2, 3 and 4), and the controlmodule (e.g. the control module 232, 332 and 432 in FIGS. 2, 3 and 4)can control the rotation speed of the fan according to both thetemperature and the power of the processor. For example, in anembodiment, when the temperature measured by the temperature sensingmodule (220, 320 and 420) is higher than a predetermined temperatureupper limit, the control module (e.g., 232, 332 or 432) controls the fan(e.g., 240, 340 or 440) to increase its rotation speed; and, when thetemperature of the temperature sensing module (e.g., 220, 320 or 420) islower than a predetermined temperature lower limit, the control module(e.g., 232, 332 or 432) controls the fan (e.g., 240, 340 or 440) todecrease its rotation speed. Oppositely, in another embodiment, when thetemperature is higher than the predetermined temperature upper limit,the control module (e.g., 232, 332 or 432) controls the fan (e.g., 240,340 or 440) to increase the rotation speed; and when the temperature isnot higher than the predetermined temperature upper limit, the controlmodule (e.g., 232, 332 or 432) controls the rotation speed of the fanaccording to the power.

Method For Controlling Rotation Speed of the Fan

The fan control system of the present invention has been fully describedabove. In addition to the fan control system, the present inventionfurther provides a method for controlling the rotation speed of the fan.

FIG. 5 is a flow chart of the method for controlling the fan controlsystem according to an embodiment of the present invention. The method500 comprises: in step S502, measuring the power of the processor; andin step S504, controlling a rotation speed of a fan according to thepower of the processor. In this embodiment, the step S504 furthercomprises: controlling the fan to increase the rotation speed when thepower is higher than a predetermined power upper limit (sub-step S504A);and controlling the fan to decrease the rotation speed when the power islower than a predetermined power lower limit (sub-step S504B). Forexample, steps S502 and S504 can be respectively performed by the powermeasurement module 260 and the control module 232 in FIG. 2. After stepS504, the process returns to step S502.

FIG. 6 is a flow chart of the method for controlling the fan controlsystem according to another embodiment of the present invention. Themethod 600 comprises: in step S602, measuring the power and thetemperature of the processor and temperature (at the same or differenttime); in step S603, controlling the rotation speed of the fan accordingto the temperature of the processor; and in step S604, controlling therotation speed of the fan according to the power of the processor. Inthis embodiment, the step S603 further comprises: controlling the fan toincrease rotation speed when the temperature is higher than apredetermined temperature upper limit (sub-step S603A). However, if themeasured temperature is not higher than the predetermined temperatureupper limit, the process goes to step S604. In this embodiment, the stepS604 further comprises: controlling the fan to increase the rotationspeed when the power is higher than a predetermined power upper limit(sub-step S604A); and controlling the fan to decrease the rotation speedwhen the power is lower than a predetermined power lower limit (sub-stepS604B). After step S604, the process returns to step S602. For example,the step S602 can be performed by the power measurement module 260 andtemperature sensing module 220 in FIG. 2, and the step S603 and S604 canbe performed by the control module 232 in FIG. 2. Those skilled in theart can understand the method of the present invention by referring tothe embodiments of the fan control system of the present inventiondescribed above, and therefore the method will not be further discussed.

While the invention has been described by way of example and in terms ofthe preferred embodiments, it is to be understood that the invention isnot limited to the disclosed embodiments. To the contrary, it isintended to cover various modifications and similar arrangements (aswould be apparent to those skilled in the art). Therefore, the scope ofthe appended claims should be accorded the broadest interpretation so asto encompass all such modifications and similar arrangements.

What is claimed is:
 1. A fan control system for processor, comprising: afan, configured to cool the processor; a power measurement module,coupled between the processor and a power supply of the processor,configured to measure the power of the processor; and a control module,coupled between the fan and the power measurement module, configured tocontrol a speed of the fan according to the power of the processor,wherein when the power is higher than a predetermined power upper limit,the control module control the fan to increase the rotation speed. 2.The fan control system as claimed in claim 1, wherein when the power islower than a predetermined power lower limit, the control modulecontrols the fan to decrease the rotation speed.
 3. The fan controlsystem as claimed in claim 1, wherein the control module furthercomprises a current sensing unit, configured to measure a current thatthe power supply provides to the processor.
 4. The fan control system asclaimed in claim 3, wherein the control module calculates the power ofthe processor according to the current that sensed by the currentsensing unit, and a voltage that corresponds to the current and is readfrom a correspondence table .
 5. The fan control system as claimed inclaim 3, wherein the control module further comprises a voltage sensingunit configured to measure a voltage that the power supply provides tothe processor.
 6. The fan control system as claimed in claim 5, whereinthe control module calculates the power of the processor according tothe current that sensed by the current sensing unit, and the voltagethat sensed by the voltage sensing unit.
 7. The fan control system asclaimed in claim 1, further comprising: a temperature sensing unit, forsensing temperature of the processor.
 8. The fan control system asclaimed in claim 7, wherein the control module controls the rotationspeed of the fan according to the temperature of the processor, whereinthe control module controls the fan to increase the rotation speed whenthe temperature is higher than a predetermined temperature upper limit.9. The fan control system as claimed in claim 7, wherein the controlmodule controls the fan to decrease the rotation speed when thetemperature is lower than a predetermined temperature lower limit. 10.The fan control system as claimed in claim 7, wherein when thetemperature is not higher than the predetermined temperature upperlimit, the control module controls the rotation speed of the fanaccording to the power of the processor.
 11. The fan control system asclaimed in claim 1, wherein the control module is disposed in anembedded controller.
 12. A fan rotation speed controlling method,comprising: measuring the power of the processor; controlling a rotationspeed of a fan according to the power of the processor, furthercomprising: controlling the fan to increase the rotation speed when thepower is higher than a predetermined power upper limit; and controllingthe fan to decrease the rotation speed when the power is lower than apredetermined power lower limit.
 13. The fan rotation speed controllingmethod as claimed in claim 12, further comprising: measuring a currentthat is provided from the power supply to the processor.
 14. The fanrotation speed controlling method as claimed in claim 13, furthercomprising: calculating the power of the processor according to themeasured current, and a voltage that corresponds to the measured currentand is read from a correspondence table between the voltage and thecurrent.
 15. The fan rotation speed controlling method as claimed inclaim 13, further comprising: measuring a voltage that the power supplyprovides to the processor.
 16. The fan rotation speed controlling methodas claimed in claim 15, further comprising: calculating the power of theprocessor according to the measured current and the voltage.
 17. The fanrotation speed controlling method as claimed in claim 12, furthercomprising: measuring the temperature of the processor.
 18. The fanrotation speed controlling method as claimed in claim 17, furthercomprising: controlling the rotation speed of the fan according to thetemperature of the processor, further comprising: controlling the fan toincrease the rotation speed when the temperature is higher than apredetermined temperature upper limit; and controlling the fan todecrease the rotation speed when the temperature is lower than apredetermined temperature lower limit.
 19. The fan rotation speedcontrolling method as claimed in claim 17, further comprising:controlling the rotation speed of the fan according to the temperatureof the processor, further comprising: controlling the fan to increasethe rotation speed when the temperature is higher than a predeterminedtemperature upper limit; and controlling the rotation speed of the fanaccording to the power of the processor when the temperature is nothigher than the predetermined temperature upper limit.